1. Field of the Invention
The present disclosure relates to liquid crystal technology, and more particularly to a self-healing gate driving circuit.
2. Discussion of the Related Art
The Gate Driver On Array (GOA) relates to integrating row-scanning driving signal circuit on array substrates through the conventional thin film transistor liquid crystal display (TFT-LCD) array manufacturing process perform so as to achieve row-by-row-scanning toward the gate.
The current GOA circuit usually includes the plural GOA units connected in cascade. Each of the GOA unit are configured to drive the corresponding horizontal scan line. The main construction of the GOA unit includes the pull-up circuit, the pull-up control circuit, the transfer-down circuit, the pull-down circuit, the pull-down holding circuit, and the boast capacitor for pulling up the potential.
The pull-up circuit is mainly responsible for outputting the clock signal as the gate signal. The pull-up control circuit is for controlling the turn-on time of the pull-up circuit, which is generally connected to the downward signal or the gate signal transferred from the previous level GOA unit. The pull-down circuit is for pulling down the gate to a low-potential, which means turning off the gate signal. The pull-down holding circuit is for holding the outputting signal of the gate and the gate signal of the pull-up circuit (usually named as the point Q) in the turn-off state (negative potential), and there are usually two pull-down holding circuits working alternatively. The boast capacitor is for the second pull-up of the point Q, which contributes to the G(N) output of the pull-up circuit.
1. According to the practical experiences, the pull-down holding circuit of the GOA circuits is most likely to be affected by the long stress, which will cause the break of some key TFTs, and thus increases the possibility of malfunctioned GOA circuits. Further, since the design of the current GOA circuits are not capable of self-healing, the possibility of such risk is highly raised.
2. During the GOA manufacturing process, due to the plenty of the circuit levels and the TFT numbers, the TFT may be short-connected or broken. Especially if such kind of situation happens in the pull-down holding circuit, the pull-down holding circuit remains in the turn-on or turn-off state, which will affect the outputted waveform from Gate. Further, as it is not easy to fix the GOA circuit, the yield rate of the liquid crystal display (LCD) will be highly affected.
3. In practices, since there is a huge resistor-capacitor (RC) loading in the GOA circuit, resulting in great delay of the gate waveform, how to decrease the gate delay is deeply concerned. The turn-off state of the pull-down holding circuit during the period of outputting the gate waveform will directly affect the delay of the Gate waveform.